Page 185 - Demo

General Discussion1839promising short-term results, the non-inferiority of ACL repair versus ACL reconstruction in the midterm remains questionable so far.17Efforts that have been made to enhance accuracy in the drilling of the femoral tunnel include the use of intraoperative fluoroscopy and computerassisted surgery (CAS). Both techniques strive to enhance accuracy in terms of achieving a planned femoral tunnel. Conflicting results are reported in CAS for femoral tunnel placement.9 Neither fluoroscopy nor CAS take the footprint of the native ACL into account. These techniques aim for a mean average position of the ACL – the empirical optimal point. This point can be better referred to as a ‘suboptimal point’, as there is wide variability in the size and location of the footprint of the ACL.28 This may lead to a partial anatomic or non-anatomic reconstruction in a number of patients. Identifying the exact location of the footprint of the native ACL should be done in order to aim for the correct femoral tunnel position. A future question that needs to be addressed is the amount of coverage of the ACL footprint during reconstruction. This footprint is shown to vary in size from 60 mm2 to 130 mm2, about half of it being reserved for each bundle.23 An average hamstrings graft of 8 mm in diameter can cover an area of about 50 mm2 ( ), which increases to about 80 mm2 when a 10-mm graft is harvested. It is shown that full dimensions of the femoral footprint of the ACL can be accurately determined on MRI.35,36 Bearing this in mind, we can preoperatively assess the diameter of the graft needed and position the femoral tunnel anatomically. To restore a native situation, all we should wish for then is a tissue-engineered ACL that resembles the native ACL in all its dimensions and properties, including mechanoreceptors.When using patient-specific instrumentation for ACL reconstruction some challenges remain though. As described above, identification of the femoral footprint of the ACL needs to be developed further. Up to now we have only aimed for a single selected point with a diameter of 2 mm, which for practical purposes was in the centre of the ACL. Ideally, this identification process should be automated. In the near future it may be possible to determine the femoral footprint of the native ACL using Mark Zee.indd 183 03-01-2024 08:56